Where does nicotine act in the body?

Nicotine binds to and activates nicotinic acetylcholine receptors (nAChRs) on the post-synaptic membrane, primarily in the central nervous system. These receptors are ion channels that allow the flow of ions across the membrane, leading to depolarisation and the transmission of a nerve signal.

Within the central nervous system, nicotine primarily affects the mesolimbic dopamine system, which is a network of brain regions involved in reward and pleasure. Nicotine acts on nAChRs in this system, triggering the release of dopamine, which is associated with sensations of pleasure and reinforcement. This positive reinforcement effect is what drives the addictive properties of nicotine and contributes to the continued use of tobacco products despite their negative health consequences.

In addition to the central nervous system, nicotine can also affect nAChRs in other parts of the body, such as the peripheral nervous system and the autonomic ganglia. These effects include increasing heart rate, blood pressure, and respiratory rate, as well as relaxing smooth muscles in the airways and digestive system.